[desktop] Clean up game list code, fix external watcher crash, and fix macOS flickering (#4106)

- Remove unnecessary icon update code (the UI reloads this stuff anyways); test on Windows please
- Cleaned up a bunch of duplicated/unused code within the game list
- Fix the game list constantly reloading on macOS
  * When you reconstruct the entire directory list on the watcher the directoryChanged signal fires on macOS--seems like a behavioral change that occurred somewhere in the 6.8 release cycle--and it would enter an infinite loop very quickly
  * To fix this, only the differences between the current and old watch list are accounted for on both ends.
  * Since this bug is now fixed, macOS uses Qt 6.11.1 now. Should theoretically improve our situation.
- Fix the external content watcher crashing; the worker would attempt to read files that didn't exist without any bounds since its cache was still pointing to that file.

This supersedes and replaces #4099.

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4106
Reviewed-by: Lizzie <lizzie@eden-emu.dev>
Reviewed-by: MaranBr <maranbr@eden-emu.dev>

src/yuzu/game/game_tree.cpp

@@ -8,8 +8,9 @@
 
 #include "qt_common/config/uisettings.h"
 #include "qt_common/game_list/game_list_p.h"
-#include "yuzu/game/game_tree.h"
 #include "qt_common/game_list/model.h"
+#include "yuzu/game/common.h"
+#include "yuzu/game/game_tree.h"
 
 GameTree::GameTree(QWidget* parent) : QTreeView{parent} {
     setAlternatingRowColors(true);
@@ -139,28 +140,7 @@ void GameTree::ApplyFilter(const QString& edit_filter_text, GameListModel* model
 
             const QStandardItem* child = folder->child(j, 0);
 
-            const auto program_id = child->data(GameListItemPath::ProgramIdRole).toULongLong();
-
-            const QString file_path =
-                child->data(GameListItemPath::FullPathRole).toString().toLower();
-            const QString file_title =
-                child->data(GameListItemPath::TitleRole).toString().toLower();
-            const QString file_program_id =
-                QStringLiteral("%1").arg(program_id, 16, 16, QLatin1Char{'0'});
-
-            const QString file_name =
-                file_path.mid(file_path.lastIndexOf(QLatin1Char{'/'}) + 1) + QLatin1Char{' '} +
-                file_title;
-
-            auto ContainsAllWords = [](const QString& haystack, const QString& userinput) {
-                const QStringList userinput_split =
-                    userinput.split(QLatin1Char{' '}, Qt::SkipEmptyParts);
-                return std::all_of(userinput_split.begin(), userinput_split.end(),
-                                   [&haystack](const QString& s) { return haystack.contains(s); });
-            };
-
-            if (ContainsAllWords(file_name, edit_filter_text) ||
-                (file_program_id.size() == 16 && file_program_id.contains(edit_filter_text))) {
+            if (Yuzu::FilterMatches(edit_filter_text, child)) {
                 setRowHidden(j, folder_index, false);
                 ++result_count;
             } else {